import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: MENG
 * Date: 2022-07-18
 * Time: 22:27
 */
public class Test {

    //考试第二题，合并两个有序数组
    public void merge(int A[], int m, int B[], int n) {
        int i = m-1;
        int j = n-1;
        int k = m + n -1;
        while(i >=0 && j >= 0){
            if(A[i] > B[j]){
                A[k] = A[i];
                i--;
                k--;
            }else{
                A[k] = B[j];
                j--;
                k--;
            }
        }
        while(i >= 0){
            A[k] = A[i];
            i--;
            k--;
        }
        while(j >= 0){
            A[k] = B[j];
            j--;
            k--;
        }


    }

    //考试第一题，删除重复字符
    public static String func(String str) {
        boolean[] flg = new boolean[255];
        StringBuilder  stringBuilder = new StringBuilder();
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if(flg[ch] == false){
                stringBuilder.append(ch);
                flg[ch] = true;
            }
        }
        return stringBuilder.toString();
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        //多组输入
        while(scanner.hasNextLine()){
            String str = scanner.nextLine();
            String ret = func(str);
            System.out.println(ret);
        }
    }
}
